Re: kirkwood devicetree respin

[Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>]

On Tuesday 20 March 2012, Andrew Lunn wrote:
> > Is there a scenario where someone would want to select
> > CONFIG_USB_EHCI_MV in menuconfig?
> 
> Not on an Orion platform, as far as i know. Maybe
> 
> config USB_EHCI_MV
>         bool "EHCI support for Marvell on-chip controller"
> -        depends on USB_EHCI_HCD
> +        depends on USB_EHCI_HCD && !PLAT_ORION
>         select USB_EHCI_ROOT_HUB_TT
>         ---help---
>           Enables support for Marvell (including PXA and MMP series) on-chip
>           USB SPH and OTG controller. SPH is a single port host, and it can
>           only be EHCI host. OTG is controller that can switch to host mode.

Well, rihgt now you can select it on anything, including non-ARM architectures,
and it fails whenever you select it in addition to another platform
driver.

If you want to add a dependency, it should be

	depends on PLAT_PXA

Most other platform drivers have a dependency on the platform
they are for, but USB_EHCI_MV was only recently added, and nobody
has bothered to fix this yet.

> Maybe also -Werror for that one file to catch other similar cases?

No, we are actually trying to make sure that any configuration you pick
results in a kernel that builds, so that would be counterproductive.

The problem will be much bigger when we get to the point where you
can actually build a multiplatform kernel, e.g. one that works
on both PXA and Kirkwood because then it will still be broken
for at least one of the two.

We recently had a discussion about how to solve this correctly, see
the email thread at http://lkml.org/lkml/2012/2/25/45 leading
up to http://lkml.org/lkml/2012/2/28/299 .
The problem is the same for ehci and ohci, and I think a lot of
people would welcome a proper fix for the situation.

	Arnd
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